What is "bryennios"

Bryennios or Bryennius , feminine form Bryennissa , was the name of a noble Byzantine family which rose to prominence in the 11th and 12th centuries, mostly as military commanders. The etymology of the name is uncertain. The first members of the family appear in the 9th century, with the strategos Theoktistos Bryennios. None are known for the 10th, but they reappear in the latter half of the 11th century, when they rose to high military commands and became associated with the Komnenian dynasty. Members of the family retained high positions through the 12th century, and are documented up to the 15th century.